Neuronal types contributing to the inner plexiform layer of the cat retina were studied using primarily light microscopy of Golgi-impregnated retinal whole-mounts. Cells have been characterized on morphological criteria that include dendritic branching patterns, dendritic tree sizes, cell body sizes and stratification of processes in the inner plexiform layer. Nine different types of bipolar cells, 22 different types of amacrine cells and 23 different types of ganglion cell were distinguished using one or more of these morphological criteria. The significance of the different morphological types of cells has been analyzed in relationship to the functional bisublamination of the cat inner plexiform layer.